288 DESCRIPTIONS OF MINERALS. 
Saxony, is the principal locality of pycnite. It is there as- 
sociated with quartz and mica. 
Trumbull, Conn., is a prominent locality of this spocies 
in the United States. It seldom affords fine transparent 
crystals, except of a small size ; these are usually white, oc- 
easlonally with a tinge of green or yellow. ‘The large coarse 
crystals sometimes attain a diameter of several inches (rare- 
ly six or seven), but they are deficient in lustre, usually of 
a dull yellow color, though occasionally white, and often 
are nearly opaque. Itis found also at Crowder’s Mountain 
in N. C.; in Utah, in Thomas’s Mountains, and in gold 
washings in Oregon. 
The ancient ¢opazion was found on an island in the Red 
Sea, which was often surrounded with fog, and therefore 
difficult to find. It was hence named from fopazo, to seek. 
This name, like most of the mineralogical terms of the an- 
cients, was applied to several distinct species. Pliny describes 
a statue of Arsinoe, the wife of Ptolemy Philadelphus, four 
cubits high, which was made of topazion, or topaz, but evi- 
dently not the topaz of the present day, nor chrysolite, 
which has been supposed to be the ancient topaz. It has 
been conjectured that it was a jasper or agate; others have 
supposed it to be prase or chrysoprase. 
Topaz is employed in jewelry, and for this purpose its 
color is often altered by heat. ‘The variety from Brazil as- 
sumes.a pink or red hue, so nearly resembling the Balas 
ruby, that it can only be distinguished by the facility with 
which it becomes electric by friction. Beautiful erystals 
for the lapidary are brought from Minas Novas, in Brazil. 
When cut with facets and set in rings, they are readily mis- 
taken, if viewed by daylight, for diamonds. From their 
peculiar limpidity, topaz pebbles are sometimes denomi- 
nated ‘gouttes Weau. 
The perfect cleavage of topaz makes it a poor substitute 
for emery. 
Euclase. 
Monoclinic. In oblique rhombic prisms, with cleavage — 
highly perfect parallel to the clinodiagonal section, afford- 
ing smooth polished faces. 
Color pale green to white or colorless, pale blue. Lustre 
witeous ; :transparent,..Brittle.. H:=75. G.=o7). ) eames 
electric. 

